Document separating apparatus



Dec. 1, 1964 K. F. ZYBER 3,159,397

DOCUMENT SEPARATING-APPARATUS Filed Dec. 12, 1962 3 Sheets-Sheet 1 Fig.1.

INVENTOR KENNETH E ZYBER. Y

ATTORNEY.

Dec. 1, 1964 Filed 'Dec. 12, 1962 Fig. 2.

K. F. ZYBER DOCUMENT SEPARATING APPARATUS 3 Sheets-Sheet 2 INVENTORKENNETH E ZYBER.

ATTORNEY 1964 K. F. ZYBER DOCUMENT SEPARATING APPARATUS 3 Sheets-Sheet 3Filed D60. 12, 1962 u mwgwx 5 R 8 w J m a 5 my 2 w 2 a :w n n Mn 1 H a vw M M M M I H ATTORNEY.

United States Patent 3,159,3h7 DGCUIWENT SEPARATENG APPARATU$ Kenneth F.Zyber, Novi, Mich, assignor to Burroughs Corporation, etroit, Mich, acorporation of Miehigan Filed Dec. 12, E62, er. No. 244,108 13 Claims.(til. 271-34) This invention relates to document handling apparatus,and, more particularly, to apparatus for demand operated documentfeeders feeding documents at a high rate of speed.

The invention is specially suited for use with a demand operated, highspeed friction feeder feeding documents, such as punched tabulatingcards, one at a time on demand through the feed exit of a card hopper topower driven accelerating drive rollers from which the card is fed toanother destination.

The invention has among its objects to provide, in a demand operateddocument feeder feeding documents from a stack of documents in a feedhopper, a document separator structure that effectively separates adocument fed on demand by the feeder and prevents a subsequent documentfrom being carried therewith to the drive rollers until a subsequentoperation of the demand feeder.

A related object is to provide, in apparatus of the above character, adocument separator structure in which the driving force is appliedthrough the separator area for driving the document therethrough andseparating it from adjacent documents, which are effectively preventedby the separator structure from progressing through the separator areain both the feeding and non-feeding operating modes of the frictionfeeder.

Another object is to provide a document separating structure for ademand operated feeder providing both frictional separation and fixedthroat separation.

A specific object is to provide in apparatus of the above character avariable gap separator providing two different separating gaps in thefeeding and non-feeding modes of the feeder.

A related object is to provide a frictional separator structure for ademand operated friction feeder in which the separator is not subjectedto any wear from the friction feeder in the non-feeding mode of thefeeder.

Another object is to provide a document separator structure foraccomplishment of the foregoing ends which is of simple construction, ispossessed of relatively durable wearing qualities and long service lifeand enables effective separating action for a demand feeder withoutrestricting the speed rate thereof.

The above and other objects together with the features, advantages andmanner of accomplishment thereof will appear more fully from aconsideration of the following detailed description and drawings,wherein:

FIG. 1 is a plan View on a reduced scale and with parts broken away of acard handling and friction feeder apparatus incorporating the documentseparating structure of the present invention;

FIG. 2 is a sectional elevation view taken along the line 22 of FIG. 1with some parts broken away;

FIG. 3 is an enlarged view with parts broken away of a portion of thefeeder and separator section of FIG. 1 and illustrated in a feedingposition;

FIG. 4 is a portion of FIG. 3 illustrating the separator structure inthe non-feeding position of the feeder;

FIG. 5 is a perspective view of a stripper guide plate in the feeder andseparator section of FIG. 1; and

FIG. 6 is a simplified electrical control circuit diagram forcontrolling the operation of the feeder.

Referring to the drawings, a portion of a document handling card feederand reader mechanism 10 is shown 3,l5,397 Patented Dec. 1., 1964 in FIG.1 in which a stack 12 of documents, such as punched cards, is supportededgewise in a feed hopper 14 and successively presented to a feedingstation 16 from which the cards are fed singly on demand past a readingstation 18 to a turn around guide roller 20 from which they are stackedin a stacking hopper 22 in the same order in which they were fed.

The feed hopper 14 includes a stationary floor plate 28 and anoscillatable floor plate 29 mounted on a base casting 26; a left endwall formed by an upstanding, rearwardly extending stripper or guideplate 32; a laterally extending edge guide 33 slidably mounted on themovable floor plate 29; a rearwardly extending pusher plate 36overhanging the hopper edge guide and floor plates; and

an empty hopper switch 37 having a card sensing actuator 38 projectingthrough an opening in the stripper plate. The pusher plate 36 ispivotally mounted and supported from an upstanding bracket 40, which issecured to a bored pilot or bearing block 42 coaxially slidably receivedon a laterally extending cylindrical guide tube 44 that is mounted onthe base casting 26. The pusher plate is urged leftwardly toward thestripper plate by a vertically spaced pair of horizontally extendingcables 45, 46 connected respectively between the block 42 and a lug 47on bracket 4%) and to coiled spring tensioning devices 48 and 49 whichare mounted from the base plate and are tensioned as the pusher plate 36is moved manually rightwardly to receive a stack of cards.

The feeder 16 is disclosed and claimed in copending US. patentapplication S.N. 244,030 filed December 12, 1962, in the name ofRobert 1. Barber, for Document Handling Apparatus, and includes aconstantly driven, endless feed belt Bil, which is formed of rubber andpasses over one face of a belt back-up member or platen 52. Platen 52 isdisplaced behind, but is movable upon demand from a solenoid actuatorassembly 54 past the stripper plate 32 to position the belt forfrictional engagement with the first or leftmost card of the stack. Thecontinuously traveling belt drives the card edgewise and rearwardlybetween a spaced pair of upstanding guide plates 56, 58 forming adocument guideway and past a separator and throat block region 60 in thefeed exit of the hopper. From the feed exit the card is fed by thefeeder into the bight of a card pull-out, accelerating drive rollerassembly 62 and past a photo-optical card detector 64, which detects thepresence of the card and de-energizes the solenoid actuator 54 toretract the belt carrying platen from the card stack. From the pull-outdrive roller assembly, the card is transported thereby between the guideplates and past the card reading station 18 by a cotton belt 65, driveroller 66 and cooperating idler, belt tensioning, and pressure rollers67, 68 and 69, 70 and then around the turn around guide roll 20 fromwhich the card is directed into the card stacker 22.

The feed belt 55) is driven in acounterclockwise direction from a drivepulley 1&2 secured to the upper end of a vertically extending tubularshaft 104, the lower portion of which below the base casting 26 mountsanother pulley 1% which is constantly driven by belt 1&8 from anelectric drive motor 110. Spaced rearwardly of the drive pulley 162 isan adjustable idler and belt tensioning pulley 112, and located inwardlyand to the right of the drive pulley 162 and crowned idler pulley 112 isa pair of forwardly and rearwardly spaced reverse idler rollers 124 ofribbed configuration corresponding to the ribbed sectional configurationof the feedbelt. *rom the reverse idler rollers 124, the feed belt 50passes around a pair of forwardly and rearwardly spaced idler rollers14?. carried by and rotatably mounted on the movable platen 52 whichprovides a rigid backing surface for the reach of e belt extendingbetween the platen idler rollers 142.

Liv

a Located to the left of and behind the platen is a shock mount and pushrod housing 162 of generally hollow, cylindrical formation and having atthe end thereor ad acent the, platen a pair of integrally formed faceflanges 163, .164 each of which contains in a bored opening 16'? thereina resilient shock mount 165, 1st to which the platen is fastened nearits extremities by screws172, as shown in FIG. 3. Projecting beyond thebase or lower endo'i the shock mount housing is a pair of integrallyformed base flanges 1'76, 177 each having an elongated adjustment slotas 178 therein for reception or a cap screw as 179 through which thehousin is adjustably positionably mounted and releasably secured to asubplate L34.v Sub-plate 134 is adjustably mounted on a pedestal block136 fastened to the base plate as shown inrto. 2.

Located internally of the housing 162 is an upstanding stop and guideblock 182 for a resiliently mounted elongated pin or push rod 284resiliently mounted as shown inFlG, 3 through a spaced pair of innershock mounts"185, 1t57 similar to the shock mounts 165, 1&6. The rightend of the push rod 184 abuts the central portion of the platen 52 andhas a threaded opening therein to receive a threaded machine screw Ztllby which the central portion of the platen is positioned and secured tothepushrod and drawn against the inner right shock mount 187. The stopblock extends through an elongated slot in the base portion of thehousing 162 and is secured at its lower end to the sub-plate 13s bymachine screws as shown in PEG. 2. The upper end of the guide spacedpair of shoulders 1%, 1?? located near the opposite endsthereof andbearing against the inner SdOCii mounts as shown. The shoulder ass isreceived between thexspaced walls of a cross-slot 21% extendingtransversely of'and formed in the yoke-shaped upper end of the guidesolenoid actuator assembly 54 which includes a two-piece cup-shaped,non-magnetic housing 214 having a flanged w baseportion 2l6 withelongated slots therein by which it isajdjustably positioned andsecured'to the sub-plate 134 by machine screws, as shown in FIGS. 1 and3. The solenoid unit includes an electrically energizable, annular fieldcoil224, whichsurrounds a cylindrical, non-magnetic Shaft Z ZS that issupported in spaced sleeve bushings 228 at 'opposite ends of thesolenoid housing; Press-fitted on the shaft 226 is an annular armaturering composed of magnetizable soft iron material received in an annularrecess or cavity of the coil. Upon energization of the coil, the ring isattracted inwardly of the solenoid coil and carries therewith thereciprocable shaft 226, which is infcontact with the rounded end 2120-5the push rod 184 through which the platen and belt are displacedtransversely of the stripper plate. The armature shaft and push rod arelimited in their movement by the central shoulder ass on the push rodlimiting against the right side or wall of the cross slot 219 in thestop block 182. The width of the cross slot is such as to permit thefeed belt carried by the platen in the actuated position of the latterto project a sufiicient predetermined distance beyond the stripperplate.

The stripper plate 32 is secured to the pedestalblock 136 and, as shownin FIG. 5, includes an elongated slot or opening 15?. therein definedbetween a spaced pair of converging and longitudinally rearwardlyextending flange portions 15%, 155 struck out of the plate. Theparallel, vertically'spaced edges 156, 157 of the flanged portions ofthe stripper plate overhang the stationary hopper floor plate 28 and arelocated in a vertical plane in advance of the normal position of theperipheral face of the feed belt in the retracted position of theplaten, as shown in FIG. 2. The feed belt and platen are located in theopening 152 and leftwardly behind the flange edges 156, is? so as to bespaced from the first card of the card stack urged against andcontacting the flange edges of the stripper plate. Located above theupper flanged portion 154 and spaced longitudinally of the stripperplate are several laterally extending aligning pins 16% fastened to thestripper plate a distance above the feed hopper floor to engage-theupper longitudinal edges of the card stack to maintain the cards incorrect vertical registration position for presentation to the feedbelt. The surface of the feed belt is ridged as shown at 51, the ridgecontacting the surface of a tabulating card between adg'acent rows ofperforations therein and being of a width approximately equal to thelength or vertical dimension of a punched hole therein.

The rcarwardiy extending rail extensions 15%, 159 of the hanged portionsof the stripper plate extend beyond the card stack and past the feedexit of the feed hopper into thesepa'rator area seam, in the retractedor nonl'eeding position of the feed belt, cooperate with the adjacentface of the adjustable' separator block lot to provide a separatorthroat bloclt having a fixedgap of a width, slightly. greater than thethickness of one card. it will be noted that the longitudinal reach ofthe feed belt over the face of the platen extends rearwardly beyond theextension rails of the stripper plate and, upon actuation of the platen,is moved transversely of the stripper pl'ateinto the throat gap where itcooperates with the adjacent face, ofthe separator block to provide aseparator gap of lesser width than the aforesaid fixed throat gap foreffective frictional separation of a card from the stack in the actuatedposition of the platen in which the feeding force of the belt issupplied through tie separator area.

The separator block 161 or cartridge is formed of a frictional,resilient compressible material, such as cellular urethane foam with anadiprene rubber base and of durable wearing quality, and having a highercoefiicient of friction relative to a card than that between adjacentdocuments or cards but less than the coelhcient of friction of therubber feed belt with the cards. The block is shown in FIGS. 4 and 5, assurrounded, on all sides except theinclined separator face 242thereof,by a metallic shield 282, the forward'portion 233 of which p-rivides ahard protective metallic facing for the portion of the block adjacentthe rearwardly disposed end of the card stack in the feed hopper. Theseparator block is included in an assembly which includes a separatorpedestal mount 2% that is fastened to the time plate 26 and has stackedthereon'an adjustable intermediate block 292 and a housing 294, whichreceives the separator block and shield as a cartridge and is mounted onthe intermediate block.

The upper surface of the pedestal mount 2% has a raised guide ridge. orkey integrally formed thereon and received in a complementary groovedguide or keyway formed in the bottom surface of the intermediate block,

which is adjustably positionable on the pedestal mount by a graduatedpositioning screw 304- that is longitudinally fixed in theintermediateblock and is threadably received in the cartridge housing.The bottom-surface of the separator block housing has a similar butshorter integrally formed projecting ridge or key received in. acomplementary grooved guide or lieyway in the adiacent surface of theadjustable intermediate block and is re- A leasably, clamped thereto bya lock screw 3% threadably of the shipper plate. The separator gap is ofsutficient width to allow only one card to pass freely therethrough andis adjusted with tWo cards positioned therein to provide an extremelytight, snug, force fit that would prevent a double card thickness topass 'therethrough.

For standard tabulating cards of 0.007 inch thickness, the aforesaidfixed gap of the throat block is adjusted within the range of 0.009 to0.012 inch. The lock screw 302 is then tightened to clamp the setting ofthe intermediate block 292 to which the separator block housing issecured. The solenoid coil 224 is then energized to actuate the platenand displace the peripheral face of the feed belt a slight distancetransversely beyond or in advance of the flange edges of the stripperplate to provide the aforesaid separator gap formed between theseparator block and the peripheral face of the feed belt. This gap widthis no greater than one card thickness at the most and in the order of0.005 to 0.007 inch to provide a snug, tight fit with the thickness of asingle card positioned between the belt and the separator block. Thepressure of the belt and the adjustment of the beltto-separator blockgap width are obtained by moving the adjustably positionable sub-plate134, on which the armature and push rod housings are mounted, relativeto the pedestal block 136 on which the sub-plate is mounted, as shown inFIG. 1.

In the feeding position of the belt, the moving face of the belt is infrictional engagement with the card stack to feed a card into andthrough the feed exit separator area of the feed hopper. The aforesaidseparator gap formed between the separator block and feed belt is ofsuch width that the separator block is under pressure against the backof the first card being fed by the belt through the separator area,where there will be generated a separating, scrubbing or retarding forcewhich is greater than the frictional and cohesive forces betweenadjacent documents but is less than the feeding force supplied from thebelt through the separator area. In consequence, should two cards befed, the second card will be separated from the first by the frictionalforce of the separator. The inclined face 242 of the separator blockassists the separating action between two cards, the sec- 0nd of whichwill strike the inclined face 285 of the block and be held back therebyas it slips against the back surface of the first card, which presents alower frictional coefiicient to the second card than that between secondcard and the separator block. Since the feeding force is applied throughthe separator area, feeding will be substantially independent ofdocument stifiness and the frictional forces generated from the feedingforce in the separating area is effectively utilized to separateadjacent documents.

As the first card passes through the throat gap, it is presented to thebight of the card pull-out and accelerating drive roller assembly 62which grabs and drivingly aecelerates the separated card atapproximately the aforementioned peripheral velocity of 225 inches persecond of the feed belt. The drive roller assembly includes a pair offriction-faced drive rollers 244, which are mounted on a shaft 226driven in a clockwise direction, and a pair of idler rollers 252, whichare in yieldable contact with the driven rollers 22d and are freelyrotatably mounted in a yoke-shaped housing 256 shown in FIG. 1. Housing2-56 is resiliently mounted in a shock mount housing container 269 thatis adjustably positionable and mounted on the base casting.

Fastened to the upper portion of the guide plates 56, 58 and locatedabove the driver rollers and idler rollers of the pull-out driverassembly is a mounting for an electric lamp 264 and solar cell 266 whichconstitute the photoelectric card detector 64. The lamp projects ahorizontal light beam through an opening in the guide plate 56 andacross the card path upon the solar cell which is positioned behind anopening in the guide plate 58. The detector serves to detect thepresence of a card in the bight of the pull-out drive roller assemblyand to control the de-energization of the solenoid to retract the feedbelt behind the flange edges of the stripper plate, thereby effectivelydisengaging the feed belt from the card stack and the feeding of asubsequent card by the belt feeder. A simplified control circuit for thesolenoid actuator is shown in FIG. 6 in which the output of the solarcell is applied over conductor line 267 to an amplifier 270 having acontrol relay 272 in the output thereof with the contacts 274 of therelay connected in series with the solenoid coil 224 and the emptyhopper switch 37 to a push-button 276 or external demand signal line268.

After de-energization of the solenoid, the feeding of the separated cardis then effected from the pull-out accelerating rollers. However, thereis still a portion of the first card in contact with the adjacent cardat the time the feed belt is disengaged from the first card. While therewill no longer be any feeding force available from the retracted feedbelt, there is still a need for preventing the second card from beingcarried along the interdocument friction, particulanly since the controlapparatus controlling the feeder is not calling for a card to be fed atthis time. Thus, so long as the second card can be prevented fromentering the throat area and progressing into the bight of thecontinuously driven accelerating rollers while the first card is beingfed thereby, the second card cannot be driven by the acceleratingrollers and will remain in the position shown in FIG. 3 where it cannotbe fed until the platen is again actuated. This separation is eifectedfrom the fixed throat gap now provided between the edges of the stripperplate guide rails and the separator block, which are located as shown inFIG. 4 and spaced apart a distance that is greater than the thickness ofone document but less than the thickness of two. Should two cardsadvance into the separating area and the second card attempt to enterthe gap between the stripper rails and the inclined face 242 of theseparator block, the second card will attempt to wedge and force againstthe first and, because of the stiffness of the cards, a normal forcewill be exerted against the separator block that is sufficient toproduce the separating force necessary to retard the second card untilthe first card is fed completely past the throat block separator area.Thus the second card cannot reach the accelerating rollers, and, beingout of contact with the face of the retracted feed belt, is effectivelyseparated and retained in the separating area where it will be helduntil a subsequent demand signal is applied to the solenoid actuator toactuate the feed belt carrying platen. Since no force is applied to theseparator block from the feed belt in the retracted position thereof,the service life of the separator block is considerably increased,conducted tests on which yielding satisfactory separating actiontherefrom even after over 10 million card feed cycles of the feeder.

It can thus be seen that the invention provides a very effectivedocument separating structure for a demand operated friction feeder thatcombines the advantages of a fixed throat block separator with africtional separator without the disadvantages attending suchseparators. In the feed mode of the feeder, the feeding force issupplied through the separator area whereby the feeding and separatingforces are independent of document stiffness. In the non-feed mode,positive separation is still maintained by the fixed throat block whileno force is applied through the feeding surface of the belt to theseparator, thereby preventing unnecessary wear thereof.

What is claimed is:

l. A document feeding apparatus for edgewise feeding of successivedocuments stacked in a feed hopper out of the hopper and past the feedexit of the hopper including an elongated stripper plate extending inthe direction of the path of feeding and defining a side wall of thehopper, means urging a stack of documents in the hopper against one sideof the stripper plate, document separating means located on one side ofthe feed path in the feed exit of the hopper and spaced from thestripper plate to form a throat block separator therewith having apredetermined gap width related to the thickness of a document, a powerdriven endless belt on the other side of the stripper plate and having areach portion extending in the direction of thelongitudinal extent ofthe stripper plate past the stack of cards and into the feed exit of thehopper, a transversely movable, elongated platen member located behindthe aforesaid reach portion of the belt and extending into the feed exitof the hopper, and power operated actuator means coupled to the platenmember and operable to'move it and the aforesaid reach portion of thebelt a predetermined extent in a direction toward and transversely ofthe stripper plate to form a frictional separator between the peripheralface of the belt and the separating means spaced from the belt an amountto provide a lesser gap width than that formed between the stripperplate and said separating means in the inactivated position of theplaten member.

2. A document feeding apparatus for edgewise feeding of successivedocuments stacked in a feed hopper out of the hopper and past the feedexit of the hopper including an elongated stripper plate extending inthe direction of the path of feeding and defining a side wall of thehopper, means urging a stack of documents in the hopper against one sideof the stripper plate, document separating means located on one side ofthe feed path in the feed exit of the hopper and forming with a portionof the stripper plate a throat block separator having a predeterminedgap width greater than the thickness of one document and less than thethickness of two documents, a power driven endless belt on the otherside of the stripper plate and having a reach portion extending in thedirection of the longitudinal extent of the stripper plate past thestack of cards and into the feed exit of the hopper, a transverselymovable, elongated platen member backing and located behind theaforesaid reach portion of the belt and extending into the feed exit ofthe hopper, and power operated actuator means coupled to the platenmemberand operable to move it and the aforesaid reach portion of thebelt a predetermined amount in a direction toward and transversely ofthe stripper plate to form a frictional separator between the peripheralface of the belt and the separating means spaced from the belt an amountto provide a gap Width no greater than the thickness of a singledocument to be fed therethrough.

3. A document feeding apparatus in accordance with claim 2 above whereinsaid document separating means is structurally yieldable away from saidfeed belt by a document being fed thereby in the activated position ofthe platen member and feed belt.

4. A document feeding apparatus in accordance with claim 2 above whereinsaid document separating means is composed of resilient material and isspaced from the peripheral face of the belt a distance less than thethickness of one document being fed thereby in the activated conditionof the platen member and feed belt.

5. A' document feeding apparatus in accordance with claim 4 abovewherein said document separating means is composed of a compressiblecellular urethane foam material.

6. A card feeding apparatus for edgewise successive feeding of a stackof cards stacked in a feed hopper including an elongated stripper plateextending in the direction of feeding and defining a side wall of thehopper, means urging a stack of documents in the hopper against one sideof the stripper plate, a power driven end-less belt on the other side ofthe stripper plate, means including a rigid backing member supportingthe belt for travel in a path in the direction of the longitudinalextent of the stripper plate and movable transversely of the stripperplate, power operated actuatorimeans coupled to the belt supportingbacking member and operable to move it and the belt in a directiontransversely of the stripper plate to position the peripheral face ofthe belt a predetermined distance beyond the said one side of thestripper plate for frictional engagement with the face of the stack,means coupled to and controlling the operation of said power operatedmeans to position the belt in engagement with the stack, a power drivendrive roller assembly positioned adjacent the feed exit of the hopper toreceive the leading edge of a card still being fed and engaged by saidbelt, card presence detecting control means detecting the presence of acard fed by the belt to the bight of the drive roller assembly andcontrolling the operation of said power operated means to retract thebelt supporting backing member and the belt to the said other side ofthe stripper plate, and document separating means located in the feedexit of the feed hopper and cooperating with the feed belt to provide africtional separating action therewith when the card is being fedthereby and cooperating with the stripper plate'to provide a separatingthroat therewith when the card is being fed by the drive rollerassembly.

7. A card feeding apparatus in accordance with claim 6 above whereinsaid document separating means provides a different width separating gapwhen the card is -being fed by the feed belt than when it is being fedby the drive roller assembly.

8. A, card feeding apparatus in accordance with claim 7 above whereinthe separating gap provided with the feed belt is of lesser width thanthat provided with the stripper plate.,-

9. A card feeding apparatus in accordance with claim 8 above wherein theseparating gap provided with the cod belt is no greater than thethickness of one card and that provided with the stripper plate isslightly less than the thickness or" two cards,

10. In a document feeding apparatus for demand feeding of documentsstacked in a hopper out of the feed exit of the hopper and, includingdemand operated friction feeding means in the hopper, means urging astack of documents in the hopper towardsaid friction feeding means,power driven drive rollers receiving a document fed by said frictionfeeding means for continuing the feeding of a document fed thereto toanother destination, a narrow gap friction separator located in the feedexit of the hopper providing a frictional separating action on adocument fed on demand from the stack by the friction feeding means, awide gap throat separator in the same location of the feed exit of thehopper as said friction separator, and means disabling the frictionalseparating action provided by'said friction separator on the documentfed to the power driven rollers when that document is being fed by thedrive rollers.

11. A document feeding apparatus for successive feeding of documentsstacked in a feed hopper out of the feed exitof the hopper comprising acontinuously driven endless feed belt having a reach portion on one sideof the document feed path and extending in the direction of thelongitudinal extent of the documents past the stack of documents and thefeed exit of the hopper, means urging the stack of documents toward thefeed belt, stack hold-back means interposed between the feed belt andthe stack of documents and normally in engagement with and maintainingthe stack of documents in spaced relation from and out of engagementwith the feed belt, power operated actuating means operable to disengagesaid documents from said stack hold-back means and engage the enddocument of the stack with the feed belt, and a fixed stop located onthe other side of the document feed path in the feed exit of the hopperand spaced from the feed belt a distance approximately equal to thethickness of a document to form a frictional separator with the belt inthe stack engaged feeding condition thereof, said stop being spaced fromthe stack hold-back means a distance slightly greater than the thicknessof a document to form a throat block separator with the stack hold-backmeans in the stack engaged condition thereof.

12. A document feeder apparatus for feeding of documents stacked in ahopper through a feed exit of the hopper, comprising an acceleratingmedium in the hopper, stack hold-back means interposed between saidaccelerating medium and said stack of documents and normally engagingand maintaining said documents in spaced relation from and out offeeding engagement with said accelerating medium, actuating meansoperable to remove said documents from engagement with said stackholdback means for engagement with said accelerating medium to feed theend document of the stack through the feed exit of the hopper, meanscontrolling said actuating means to return said stack of documents intoengagement with said stack hold-back means when the leading edge of theend document has been fed past the feed exit of the hopper, and avariable gap separator including a fixed stop located in the feed exitof the hopper and successively providing for the documents adjacent theend document as the end document is fed from the stack through the feedexit of the hopper a narrow separation gap formed between the stop andthe accelerating medium while in engagement with the end document beingfed thereby and then a wide separation gap formed between the stop andthe hold-back means when the leading edge of the aforesaid end documenthas been fed past the feed exit of the hopper.

13. A document feeding apparatus for demand feeding of documents stackedin a hopper out of the feed exit of the hopper, said apparatuscomprising feeding means in the hopper operable in response to a commandsignal to engage the end document of the stack and feed it out throughthe feed exit of the hopper, a power driven drive roller assemblyreceiving the end document fed by said feeding means and continuing thefeeding thereof to another destination, a narrow gap friction separatorlocated in the feed exit of the hopper providing a frictional separatingaction on the documents adjacent the end document being fed from thestack by the feeding means, a wide gap throat separator in the samelocation of the feed exit of the hopper as said friction separator, andmeans disabling the frictional separating action provided by said narrowgap friction separator to permit the wide gap separating action of saidwide gap throat sepa rator on the documents adjacent the end documentbeing fed by the feeding means through the feed exit of the hopper whenthe aforesaid end document is being fed by the drive roller assembly.

References Cited in the file of this patent UNITED STATES PATENTS856,346 Jahn June 11, 1907 2,093,654 Bellamy Sept. 21, 1937 2,856,187Burckhardt et a1 Oct. 14, 1958 3,089,697 Brozo May 14, 1963 3,103,355Hubbard et al Sept. 10, 1963

10. IN A DOCUMENT FEEDING APPARATUS FOR DEMAND FEEDING OF DOCUMENTSSTACKED IN A HOPPER OUT OF THE FEED EXIT OF THE HOPPER AND INCLUDINGDEMAND OPERATED FRICTION FEEDING MEANS IN THE HOPPER, MEANS URGING ASTACK OF DOCUMENTS IN THE HOPPER TOWARD SAID FRICTION FEEDING MEANS,POWER DRIVEN DRIVE ROLLERS RECEIVING, A DOCUMENT FED BY SAID FRICTIONFEEDING MEANS FOR CONTINUING THE FEEDING OF A DOCUMENT FED THERETO TOANOTHER DESTINATION, A NARROW GAP FRICTION SEPARATOR LOCATED IN THE FEEDEXIT OF THE HOPPER PROVIDING A FRICTIONAL SEPARATING ACTION ON ADOCUMENT FED ON DEMAND FROM THE STACK BY THE FRICTION FEEDING MEANS, AWIDE GAP THROAT SEPARATOR IN THE SAME LOCATION OF THE FEED EXIT OF THEHOPPER AS SAID FRICTION SEPARATOR, AND MEANS DISABLING THE FRICTIONALSEPARATING ACTION PROVIDED BY SAID FRICTION SEPARATOR ON THE DOCUMENTFED TO THE POWER DRIVEN ROLLERS WHEN THAT DOCUMENT IS BEING FED BY THEDRIVE ROLLERS.